Transcript PPT Version

A Location Reference Event Package for
the Session Initiation Protocol (SIP)
draft-schulzrinne-geopriv-locationref-00
Henning Schulzrinne
Columbia University
November 2006
IETF67 - GEOPRIV
1
Goals
• Allow UA to obtain location reference or value
– RPRU = Randomized Presence Retrieval URL
• Recipient should be able to “claim” LO
– authorization by possession (“pawn ticket”)
– no need for authorization relationship between LIS
and UAS
– can subscribe to updates
• Unified LbyV and LbyR mechanism
• Single mechanism for retrieval and
subscriptions
November 2006
IETF67 - GEOPRIV
2
Reference with network identifier
UAC
LIS/
PS
UAS
SUBSCRIBE sip:lis
Event: locationref;mac=“0:..:27”
NOTIFY sip:uac
Event: locationref
sip:xu5869@lis
INVITE sip:uas
Geolocation: sip:x85869@lis
SUBSCRIBE sip:xu5869@lis
Event: presence
NOTIFY sip:uas
Event: presence
<PIDF-LO>
November 2006
IETF67 - GEOPRIV
3
AOR-based
UAC
LIS/
PS
UAS
PUBLISH sip:alice@lis
Event: presence
<PIDF-LO>
SUBSCRIBE sip:alice@lis
Event: locationref
NOTIFY sip:alice@uac
Event: locationref
sip:xu5869@lis
INVITE sip:uas
Geolocation: sip:x85869@lis
November 2006
IETF67 - GEOPRIV
4
Value with network identifier
UAC
LIS/
PS
UAS
SUBSCRIBE sip:lis
Event: presence;mac=“0:..:27”
NOTIFY sip:uac
Event: presence
<PIDF-LO>
INVITE sip:uas
Geolocation: mid:x123
Content-Type: …
<PIDF-LO>
November 2006
IETF67 - GEOPRIV
5
Event parameters
• ;ip=“128.59.16.3”
• ;mac=“0:3:fc:0:ca:27”
• ;msap=“tuyx48wuaz==“
– base64-encoded version of 802.1ab
(LLDP) MAC service access point
• ;cdp=“8th-floor/17”
– Should we define CDP switch/port
information?
November 2006
IETF67 - GEOPRIV
6
OI#1: Proof of possession
• For IP address, would like proof of possession for UA
– prevent getting locations of neighborhood UAs
• Easy if no outbound proxy and same subnet
– even with NAT (if Contact/ip= uses STUN-derived address)
• Harder with outbound proxy
– outbound proxy could compare source IP address and
Contact
– compare Via and Contact?
– only works for trusted proxy
• likely for proxy operated by ISP or VSP
• but malicious user could operate own proxy
– use STUN (on LIS)?
November 2006
IETF67 - GEOPRIV
7
OI#2: Location vs. Presence
• No separate mechanism just to subscribe to
location
– not a major issue for LIS/PS, since it only knows
location information
– can do this via watcher filter in SUBSCRIBE, if
desired
– presence ref also likely to be useful
• Proposal: change ‘locationref’ to ‘presenceref’
November 2006
IETF67 - GEOPRIV
8
OI#3: Location by value
• Need to define ‘presence’ event
package parameters
November 2006
IETF67 - GEOPRIV
9
OI#4: Finding the LIS
• DHCP --> need draft (similar to LoST
mechanism?)
• Use same mechanism as SIP
configuration -- based on UA domain
name
• Could also use zeroconf/Bonjour
discovery
November 2006
IETF67 - GEOPRIV
10